Manufacture of acetic aldehyde



UNI ED STATES PATIENT OFFICE-f HENEY DEEYEUs, F BASEL, SWITZERLAND. 7

' MANUFACTURE OF ACETIC AliDEHYDEa i No Drawing.

T 0 all whom it may coacem:

Be it known that I, HENRY DREYFUS, of

I Basel, Switzerland, have invented certain new and useful Improvements Relating to the Manufacture of Acetic Aldehyde, of which the following is. a specification.

p This invention relates to the manufacture of acetaldehyde by processes wherein acetylene is passed into sulfuric acidlsolutionscontaining mercury compounds, and in particular to the manufacture of acetaldehyde by the process described in the specification of application for United. States Patent Serial No. 172,325 (filed June l, 1917), which process permits of the industrial manufacture of acetaldehyde on a large scale and with a high yield of acetaldehyde relatively to the'quantity of mercury compound employed.

The process of said application consists briefly in first producing an acidsolution containing sulfate of mercury, then passing pure acetylene gas thereinto, slowly at first,

and when the solution turns black or grayish-black, as rapidly as'can be absorbed,-

then as soon as the avidity of. the solution for the absorption of acetylene drops off garnation with mercury.

somewhat, stopping the introduction, then distilling off the acetaldehyde formed (this being best effected in a vacuum) again cool ing the liquor andrepeating alternately the two steps of introducing acetylene and distilling the acetaldehyde from the liquid.

In my said specification Serial No. 172,325 considerable importance is attributed to the apparatus employed for the manufacture of acetic aldehyde, ,and for the manufacture on a large scale it was proposed to employ,

for the vessels or apparatus, leaden surfaces which had been treated in a certain manner whereby they are enabled to resist both the action of the dilute acid present and amal- Specification of Letters Patent.

Patented Dec. 14, 1920.

Application filed June 4; 1917.. Serial No. 172,795.

Iron, as is known, is the only common metal which does not give an amalgam with mercury, but it has the disadvantage that it is attacked and dissolved by acids, so that its employment alone would be. impossible. As the result of further researches I have now found that certain alloys of iron and silicon withstand dilute acids such as dilute boiling sulfuric acid, and at the same time have theadvantage of not forming an amalgam when employed for apparatus for processes of the character referred to. This is a surprising fact and of great technical importance. 7

By this invention it is possible to replace lead surfaces covered with a layer prepared as described in my said specification Serial No. 172,325 by ferro-silicon employed for the apparatus or parts thereof exposed to the absorption solution.

' It is thus possible to employ apparatus of very large capacity, say 1000 to 10,000 liters or more, made of cast iron alloyed with silicon. Suitable alloys for the purpose ofthe invention may contain for example 12 to 17 per cent. of silicon.

HENRY DREYFUS.

Witnesses I THOMAS LAING WHITEHEAD, ROBERT MILTON SPEARPOINT. 

